react 3rd party lib crawling for automatic `noExternal` should take custom `root` into account

Related plugins

• plugin-react

• plugin-react-swc

• plugin-react-oxc

• plugin-rsc

Describe the bug

The plugin resolves framework dependencies from the process.cwd() instead of checking the config.root: https://vite.dev/config/shared-options#root

The potential fix would be to change the following line to config.root ?? process.cwd()

https://github.com/vitejs/vite-plugin-react/blob/db9221fcec0708466329e52c2b6a187b28f78421/packages/plugin-rsc/src/plugin.ts#L471

Reproduction

https://github.com/vixalien/repro-react-router-rsc-runner

Steps to reproduce

1. Create an RSC app with the command: npx create-react-router@latest --template remix-run/react-router-templates/unstable_rsc-framework-mode
2. In another folder/package create a simple JS file that uses the Vite JS API to run the RSC app by pointing vite to the previous directory

import { createServer } from "vite";                                                                                                                                                                          
                                                                                                                                                                                                              
const server = await createServer({                                                                                                                                                                           
  root: "../app",                                                                                                                                                                                             
});                                                                                                                                                                                                           
await server.listen();                                                                                                                                                                                        
                                                                                                                                                                                                              
server.printUrls();                                                                                                                                                                                           
server.bindCLIShortcuts({ print: true });                                                                                                                                                                     

System Info

System:
    OS: Linux 6.18 GNOME OS Nightly
    CPU: (8) x64 11th Gen Intel(R) Core(TM) i7-1165G7 @ 2.80GHz
    Memory: 19.50 GB / 30.64 GB
    Container: Yes
    Shell: 5.3.9 - /bin/bash
  Binaries:
    Node: 25.6.1 - /home/alien/.local/share/mise/installs/node/25.6.1/bin/node
    Yarn: 4.12.0 - /home/alien/.local/share/mise/installs/yarn/4.12.0/bin/yarn
    npm: 11.9.0 - /home/alien/.local/share/mise/installs/node/25.6.1/bin/npm
    pnpm: 10.30.1 - /home/alien/.local/share/mise/installs/pnpm/10.30.1/pnpm
    Deno: 2.6.10 - /home/alien/.local/share/mise/installs/deno/2.6.10/bin/deno

Used Package Manager

pnpm

Logs

No response

Validations

• Follow our Code of Conduct
• Read the Contributing Guidelines.
• Read the docs.
• Check that there isn't already an issue that reports the same bug to avoid creating a duplicate.
• Make sure this is a Vite issue and not a framework-specific issue.
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• The provided reproduction is a minimal reproducible example of the bug.

Start at packages/plugin-rsc/src/plugin.ts around line 471, where framework dependencies are crawled, and compare the configured root with process.cwd(). Reproduce the issue using the linked react-router RSC example and a Vite server configured with root: "../app". Done means dependency resolution uses the configured root while preserving behavior when no custom root is provided.